AMT Calculator

The Alternative Minimum Tax (AMT) is a parallel tax system that ensures taxpayers with significant income pay a minimum amount of tax. For ISO holders, the bargain element (FMV minus strike price) at exercise is an AMT adjustment that gets added to your Alternative Minimum Taxable Income (AMTI).

The AMT Calculation

The IRS computes your tax two ways: regular tax and tentative minimum tax. You owe AMT only if the tentative minimum exceeds your regular tax. If you claim the standard deduction, the AMT calculation restores it before adding the ISO bargain element, subtracting the AMT exemption, and applying the 26% and 28% AMT rates.

AMT Credit Carryforward

AMT attributable to ISO exercise timing may generate a Minimum Tax Credit. AMT from exclusion items, such as the standard deduction, does not. In a later year, the credit is limited by the amount that regular tax exceeds tentative minimum tax. Form 8801 and your full tax return determine the actual amount.

Strategies to Manage AMT

Spreading exercises across multiple tax years can keep you below the AMT threshold each year. Exercising early in the year gives you time to do a same-year disqualifying disposition if the stock drops — which eliminates the AMT adjustment. Timing exercises with years of lower regular income can also minimize AMT impact.